Video: Add local still image and video recording [WIP]

[ddd999]

This draft PR is a work in progress to address feature request #167 and continues where PR #229 left off. It's incomplete and some parts are likely still broken. Adding the PR now for visibility into the proposed changes and to solicit feedback if there is any.

This reorganizes the camera system into three distinct modes:

• live streaming (i.e., what exists now)
• still photo capture (saved locally on the companion computer)
• local video recording (saved locally on the CC)

It adds a Python helper script to detect all of the camera devices available for still/video capture (get_camera_caps.py), and a backend/server script (photomode.py) that listens for a SIGUSR1 from Rpanion to trigger it to either take a still photo, or to toggle video recording on and off.

By default, photomode.py will use the first available camera supported by Picamera2(). If that's not available, or if a V4l2 device path is specified, it will use V4L2 instead.

To do list (for this PR):

• Testing and bug fixes as required to make sure all of the above works correctly
• Confirm that camera service still responds correctly to MAVLink commands
• Add/update unit tests

To do list for future PR(s):

• Add geotagging ability
• Implement MAVLink gimbal control
• Implement more camera settings (exposure, white balance, etc.) ([Feature Request] Custom Camera Parameter Settings #228)
• (Edit: moved to future PR to-do list) Investigate and implement measures to support Mission Planner stream auto-discovery (Add support for Mission Planner video view #282 and probably also Feature Request: send VIDEO_STREAM_INFO mavlink messages to GCS #169)

[stephendade]

Great! I'll take a look later in the week

[stephendade]

I've had a look through - looks good.

A few issues I came across during testing (on my laptop. Will try a Rpi tomorrow):

• GUI: Connection strings for video stream are missing in RTSP mode
• Still Photo mode: bugs out on "No module named 'picamera2'" for photomode.py
• Camera RTSP address not being sent to MP. Appears cam_definition_uri or CAMERA_INFORMATION is blank. Same for model_name and vendor_name. Resolution is being sent through through
• Still Photo mode: bugs out on "An error occurred creating directory: [Errno 13] Permission denied: '/home/pi'"

[stephendade]

Testing on the RPI

• Need to document that python3-opencv package is required
• Video recording mode on CSI camera. Can't start a new recording. I get:
  [API /togglevideorecording] Received request. Server state: vManager.active=false, vManager.cameraMode=video [API /togglevideorecording] Condition NOT met. Sending 400.

EDIT:
Tested taking still images from MP and worked quite well!

[ddd999]

Thanks for reviewing/testing.

I also found that in streaming mode, streaming mode stopped in the UI, but the video stream didn't actually stop.

This might be a peculiarity (or intentional behaviour?) of Mission Planner: MP only recognizes the stream the first time the VideoStreamInformation message is sent. If you stop the stream, then restart it with the same device, it doesn't recognize the stream again unless you close and restart MP. Could also be related to the aforementioned issue.

Guess there are a few things to work on still!

[stephendade]

Yeah, could be an MP-specific thing.

Happy with the overall work on the PR. Keen to get it merged in once we've ironed out the final issues.